This project attempts to determine whether photoreceptor allografts in rd-mutant mouse retina are capable of forming anatomical and functional connections with neurons of the host retina. It will also determine whether such photoreceptor allografts trophically influence the survival and function of photoreceptors in the rd- mutant mouse retina. The experiments involve electron microscopy and single ganglion cell physiology of mouse retina. The results are relevant to the treatment of photoreceptor degenerations in man.